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// SPDX-License-Identifier: AGPL-3.0-or-later
/* PASST - Plug A Simple Socket Transport
*
* qrap.c - qemu wrapper connecting UNIX domain socket to socket file descriptor
*
* Copyright (c) 2020-2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*
* TODO: Implement this functionality directly in qemu: we have TCP and UDP
* socket back-ends already.
*/
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <errno.h>
#include <linux/if_ether.h>
#include <linux/ipv6.h>
#include <linux/limits.h>
#include <limits.h>
#include <net/if.h>
#include "passt.h"
static char *qemu_names[] = {
"kvm",
"qemu-kvm",
#ifdef ARCH
"qemu-system-" ARCH,
#endif
"/usr/libexec/qemu-kvm",
NULL,
};
#define DEFAULT_FD 5
/**
* usage() - Print usage and exit
* @name: Executable name
*/
void usage(const char *name)
{
fprintf(stderr, "Usage: %s [FDNUM QEMU_CMD] ...\n", name);
fprintf(stderr, "\n");
fprintf(stderr, "If first and second arguments aren't a socket number\n"
"and a path, %s will try to locate a qemu binary\n"
"and directly patch the command line\n", name);
exit(EXIT_FAILURE);
}
/**
* main() - Entry point and main loop
* @argc: Argument count
* @argv: File descriptor number, then qemu with arguments
*
* Return: 0 once interrupted, non-zero on failure
*/
int main(int argc, char **argv)
{
char *qemu_argv[ARG_MAX], net_id[ARG_MAX] = { 0 }, *net_id_end;
int i, s, qemu_argc = 0, in_netdev = 0, has_socket = 0;
struct sockaddr_un addr = {
.sun_family = AF_UNIX,
.sun_path = UNIX_SOCK_PATH,
};
char fd_str[ARG_MAX];
long fd;
if (argc >= 3) {
fd = strtol(argv[1], NULL, 0);
if (fd >= 3 && fd < INT_MAX && !errno) {
char env_path[ARG_MAX], *p, command[ARG_MAX];
strncpy(env_path, getenv("PATH"), ARG_MAX);
p = strtok(env_path, ":");
while (p) {
snprintf(command, ARG_MAX, "%s/%s", p, argv[2]);
if (!access(command, X_OK))
goto valid_args;
p = strtok(NULL, ":");
}
}
}
fd = DEFAULT_FD;
for (qemu_argc = 1, i = 1; i < argc; i++) {
char *p;
if (in_netdev) {
in_netdev = 0;
if (strstr(argv[i], ",socket") ||
strstr(argv[i], "socket,"))
has_socket = 1;
} else if (!strcmp(argv[i], "-net") ||
!strcmp(argv[i], "-netdev")) {
in_netdev = 1;
}
if (!*net_id && (p = strstr(argv[i], ",netdev=")))
strncpy(net_id, p + strlen(",netdev="), ARG_MAX);
qemu_argv[qemu_argc++] = argv[i];
}
if (!has_socket) {
if (*net_id) {
net_id_end = strpbrk(net_id, ", ");
if (net_id_end)
*net_id_end = 0;
}
qemu_argv[qemu_argc++] = "-netdev";
snprintf(fd_str, ARG_MAX, "socket,fd=%u,id=%s", DEFAULT_FD,
*net_id ? net_id : "hostnet0");
qemu_argv[qemu_argc++] = fd_str;
qemu_argv[qemu_argc] = NULL;
}
valid_args:
s = socket(AF_UNIX, SOCK_STREAM, 0);
if (s < 0) {
perror("socket");
exit(EXIT_FAILURE);
}
if (connect(s, (const struct sockaddr *)&addr, sizeof(addr)) < 0) {
perror("connect");
exit(EXIT_FAILURE);
}
if (dup2(s, (int)fd) < 0) {
perror("dup");
exit(EXIT_FAILURE);
}
close(s);
if (qemu_argc) {
char **name;
for (name = qemu_names; *name; name++) {
qemu_argv[0] = *name;
execvp(*name, qemu_argv);
if (errno != ENOENT) {
perror("execvp");
usage(argv[0]);
}
}
if (errno == ENOENT)
fprintf(stderr, "Couldn't find qemu command\n");
} else {
execvp(argv[2], argv + 2);
}
perror("execvp");
return EXIT_FAILURE;
}
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